The present invention relates to a communication line control system including a plurality of communication terminals (communication terminal devices) each incorporating communication functions containing voice communications and data (facsimile) communications and accommodating a plurality of communication lines connected to a network. The present invention relates also to a communication line control method of controlling the plurality of communication lines in one single communication terminal, and of processing a communication on the same communication line between the plurality of communication terminals.
With diversified needs, there have been provided services for making a plurality of communication lines controllable in one single communication terminal. For example, when telephone calls occur simultaneously, an arbitrary call can be responded by allocating the line per button in a telephone terminal connected to a button telephone system or a private branch exchange (PBX).
Further, there are actualized services for increasing an operation efficiency of a telephone transfer of the call dealt with by the telephone terminal by sharing with other terminals.
On the other hand, the data dealt with by a computer terminal serving as a communication terminal are also diversified, and one computer terminal is capable of operating communications, facsimile communications, etc. other than the data communications. There are provided services and a system (Internet telephony system) incorporating a function schemed to attain more of usability by utilizing the telephone services in the computer terminal such as a personal computer (PC) by fusing the above communication functions.
For attaining the services described above, however, it is required that hardware and software (application) using the communication lines in the computer terminal be aware (such as judging which line is used for response when the plurality of calls arrive) of the number of the communication lines and data (a telephone number, etc.) of each communication line and so on.
This, however, conduces to a problem in terms of decline of simplicity in creating the software and a general-purposed characteristic to other systems due to an increase in processing load of the software and to a difference in the number of lines connected to the terminals.
Further, in the case of sharing the communication lines with other computer terminals, a conflict with other terminals might arise, and hence the software needs a process to obviate the conflict, with the result that the same problems as those described above occur.
Moreover, even if the software using the communication line in an arbitrary terminal or the terminal itself falls into an abnormal state, and if consistency with the communication lines can not be taken, the terminal is incapable of responding irrespective of a state of the terminal or the software when, e.g., telephone calls occur. This leads to a decline of respondency of the telephone.